Toxicology Flashcards by Jacqueline Butler

Tylenol

Metabolized into NAPQI by glucuronidation via glutathione stores (less in chronic ETOH)

**Think of 140!

140mg/kg is toxic dose
140 level at 4h = BAD
140mg/kg = loading dose of NAC

Antidote: N acetyl cysteine (watch for anaphylactoid rxn IV, give over 1h)
Restores glutathione which metabolizes toxic byproduct NAPQI

Rumack-Matthew Nomogram

4 phases of poisoning:

1st 24h = N/V, fatigue, sweating, abd pain (AST/ALT elevation after 18h)
24-72h = RUQ pain, dark urine, jaundice
72-96h = hematuria, fever, tachypnea, blurred vision, lethargy, confusion, coma

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Anticholinergics

Drug = Atropine, Scopolamine (can mimic antipsychotics, antihistamines, TCA’s)

Antidote: Physostigmine (reversible acetylcholinesterase inhibitor)
Manage seizures with benzo’s

Indications for physostigmine: (don’t give on exam without talking to poison control, or at all)
Hemodynamic compromise, psychosis or severe agitation.
**Can cause bradycardia, do not use if prolonged PR or QRS on initial EKG.
**Do not use if seizing, known TCA ingestion, QRS widening, reactive airway disease

Blind as a bat (mydriasis)
Mad as a hatter (AMS)
Red as a beet (hot, dry)
Hot as a hare (febrile)
Tachycardic
Loss of bowel/bladder tone (retention)

Deadly Nightshade, Belladonna, Jimson Weed

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Cholinergics

AChE inhibitors, ACH builds up…
Drug: Organophosphates, Some mushrooms, insectisides

Antidote: Atropine, 2-PAM
Atropine is muscarinic antagonist, blocks ACH peripherally. 1-2 mg IV bolus q3-5 minutes until secretions dry.
2-PAM reverses nicotinic sx - reactivates AChE by binding to OP particle instead, must be used within 48h of onset.

SLUDGE: (muscarinic)
Salivation
Lacrimation
Urination
Diarrhea
GI
Emesis
(also Bradycardia, Bronchorrhea, Bronchospasm)

Fasciculations, weakness and paralysis (nicotinic)

**If intubating, avoid Succ as it is degraded by AChE and may cause prolonged paralysis!

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Sympathomimetics

Looks just like anticholinergic but SWEATY

Cocaine, Epinephrine, Meth

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Opiates

Coma, Pinpoint Pupils, Respiratory Depression

Demerol has dilated pupils

Antidote: Narcan

Opioids are synthetic derivatives of opiates

Synthetics not on tox screens: Fentanyl, methadone, demerol… do not cross react with naturals such as codeine and morphine

Withdrawal not life threatening except in neonates, can seize. Tx neonates with clonidine patches.

Tramadol can cause seizures, risk of serotonin syndrome. Narrow therapeutic index. Basically PO demerol.

Methadone can lead to Torsades

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Iron

> 40-60 mg/kg potentially fatal (20% elemental iron sulfate)

325mg x20% x pills ingested

Stage 1: Abd pain, vomiting (hours)
Stage 2: Quiescent
Stage 3: (12-48h) Shock and metabolic acidosis
Stage 4: Liver failure and possible death
Stage 5: GI scarring

Antidote: Deferoxamine (not orally) -
Chelates the iron
WBI (charcoal ineffective)

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Isopropyl

Antidote: Fomepizole, ETOH

Possible some pneumonitis
Toxic metabolite of acetone

**Does not cause an acidosis

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Osmolar Gap

Calculated = 2NA + BUN/2.8 + Glu/18 + ETOH/4.6

Calculated minus Measured (normal = -14 to +14)

Ethylene Glycol, Methanol, ETOH, Isopropyl

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Methanol

Wood EtOH, Moonshine

Snow blindness, produces formic acid/formaldehyde

Antidote = Fomepizole, ETOH
Needs dialysis if late, already has metabolites

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Ethylene Glycol

Antifreeze

Produces glycol acid and oxalic acid
**Crystals in urine - calcium oxalate -> ATN and hypocalcemia

Hepatic and renal failure

Antidote = Fomepizole, ETOH
Needs dialysis if late, already has metabolites

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Dialysis Indications

Works for:
Ethanol (if very high)
Methanol
Aspirin
Lithium
Barbiturates
Gentamycin
Cephalosporins
Paraquat
Ethylene Glycol

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Aspirin

Acute:
>150mg/kg
Low Mortality
Tinnitus, Dizziness
Resp Alkalosis, Metabolic Acidosis

Non-cardiogenic pulmonary edema, cerebral edema

Chronic:
High mortality, old
Pseudo Sepsis

Antidote:  Bicarb
Alkalinize to pH of 7.5
Charcoal
Replace K and Mg
**Dialysis if seizures, coma, pulmonary edema, renal failure

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TCA’s

Anticholinergic-like symptoms, signs of seizures, arrythmias, apnea

EKG findings: (Na blockade)
QRS widening
R axis deviation
Terminal R wave > 3mm in aVR

Antidote = Bicarb in high doses

Na-K pump poisoning

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Methemoglobinemia

Oxidizes Fe2+ to Fe3+

Small kids, G6PD high risk
Sats at 85% despite O2, need co-ox
“Chocolate” blood

Antidote: Methylene blue, O2
Methylene blue accelerates reduction by NADH/NADPH
**Avoid in G6PD, may need exchange transfusion

Drugs = pyridium, benzocaine, Dapsone

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Carbon Monoxide

Headache, whole family is sick, dog sick

HbCO binds more than HbO2

Cherry colored skin/lips

Half life CO:
4-6 hours RA
1 hours NRB
20-30 min HBO

Needs Co-ox
PaO2/ABG not accurate
Hyperbarics if pregnant, persistent deficits, syncope, dying, or >25%
O2 by NRB

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Cyanide

Global cell hypoxia, inhibition of oxidative phosphorylation

Headache, vertigo, confusion, syncope, coma, death
Severe lactic acidosis
VBG appears arterial

**Fires with plastic burning
Bitter almond smell

Antidote = **Cyanokit which is Hydroxycobalamin (binds CN)

Or, old way (can kill if it’s CO) =
Nitrates (controlled MetHB that bones CN) then Thiosulfate

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Digoxin

Yellow halo vision
Bradycardia
PVC's
PAT with a block
Junctional rhythm with bidirectional ventricular tachycardia

EKG shows Salvador Dali mustache
Plants = Foxglove, Oleander, Lilly of Valley

Antidote = DigiFAB
Activated charcoal
Atropine may work
**Avoid TV pacing - irritable myocardium
**Avoid calcium despite hyperkalemia - will cause stone heart

**Hyperkalemia is a bad sign! (>5) in acute toxicity
Chronically low K/Mag makes more susceptible
Poisoning Na-K pump

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CCB/B-blocker

Bradycardia, hypotension, shock
**Hypoglycemia with kids

Rx = aggressive GI decontamination (charcoal if early, WBI)
Glucagon
Epinephrine, Atropine
Calcium
Hyperinsulinemia - euglycemic therapy (bypasses cAMP)
Intralipid

Beta blocker will be much more hypoglycemic, glucagon works for B-blockers
CCB is hyperglycemia

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INH

Seizing refractory to benzo’s

Antidote = B6 (pyridoxine)
1g for each gram INH

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Dialysis Contraindications

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Doesn't work for:
Digoxin
TCA's
B-Blockers
Benzodiazapines
Sulphonylureas
Phenytoin

Charcoal Contraindications

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Obtunded
Toxin with risk of seizures
Ileus
Hydrocarbons
Caustic Ingestions
Alcohols
Metals

Whole Bowel Irrigation indications

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Iron
Lithium
Sustained release agents
Enteric coated agents
Body packers (not stuffers)

1-2L/h (adults) and 500ml/h (kids)
Consider NGT and pump
Continue until clear

NSAIDs

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COX inhibitor, decreases prostaglandin production

Well tolerated acutely, acute UGI bleed uncommon.
Large ingestions: sleepy, mild ataxia or disorientations
Massive ingestions: Seizures, coma, acidosis

Chronic: PUD, analgesic nephropathy, agranulocytosis with some

Tx = Supportive

Anesthetics

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Seizures (rare recurrence due to fast metabolism)
VT/VF - Bicarb IV push
Lipid emulsion rescue IVP followed by infusion

Coumadin

Inhibit 2, 7, 9, 10 vit K dependent factors Hypercoaguable in first 2-7 days if underlying Protein C issue, so follow INR **don't give vit K if early Only treat if bleeding, otherwise just hold warfarin Actively bleeding = FFP Vit K for largely elevated INR

Heparin/LMWH

Inactivates thrombin and activate factor 10a LMWH targets anti-factor 10a Antidote = protamine 1mg per 100 units heparin HIT - antibodies that activate platelets, thrombosis

Plavix

Antiplatelet agent Can get neutropenia, hemorrhage, and TTP Tx = administer platelets

Cocaine

Inhibits re-uptake of catecholamines, also Na channel blockade HTN, hyperthermia, Rhabdo, MI, seizures, VT Tx = Benzo's, cooling, nitrates, CCB **No Beta Blockers!

Amphetamines

Causes catecholamine release HTN, Tachycardia, hyperthermia, ICH, rhabdo Tx = Benzo's, cooling, nitrates, CCB **No Beta Blockers!

GHB

Fast onset, minutes 2-6 hour duration Euphoria and prosexual properties Bradycardia, Bradypnea, Coma with rapid awakening Withdraw just like DT's Tx supportive

Crotalid features

``` Diamond head Elliptical pupil Single row of scales behind anal plate Facial pits +/- rattles ``` Indications for antivenom: Progressive swelling Thrombocytopenia

Black Widow

Found in woodpile or hidden space, not aggressive Central bite with bullseye lesion Rare "acute abdomen" with negative CT No reported deaths Tx = pain control, benzo's, possibly anti-venom but worse than actual bite Can discharge if pain controlled, ons for 6h if anti-venom given

Brown Recluse

Small, violin shape on head Southeast and Midwest only Necrotic Arachnidism Central ulcer after eschar RARE: Hemolysis, DIC, shock Supportive tx, abx if secondary infection, tetanus

Scorpion

Bark Scorpion, Arizona Small, light to dark brown, lobster claws Nocturnal Neurotoxic venom Immediate pain/paresthesia at site Autonomic effects (HTN, tachycardia, diaphoresis, N/V) can progress to paralysis Antivenom if needed, otherwise supportive care

Ciguatera

Sodium channels and cholinergic receptors ``` Onset in 6h, N/V/D Hot cold reversal Feeling of loose teeth Bradycardia Respiratory Arrest ``` Tx = Mannitol

Scombroid

Poor refrigeration of fish Histadine breaks down to histamine-like compounds Peppery taste Rapid onset, flushing, HA, N/V/D less common **if only 1 person has it, possible allergic rxn Tx = supportive

Jellyfish

Nematocysts Burning pain, pruritus, arrythmias Antidote for Box Jellies Vinegar for 30 min

Stonefish/Stingray

Dorsal spine Heat labile toxin = hot water If barb retained, explore wound well Cover for vibrio

Button Batteries

Alkali's, metals Endoscopic retrieval if larger (>penny) Past pylorus, usually watch

Clonidine

Opioid mimic Bradycardia/Hypotension Alpha agonist Supportive care Atropine for bradycardia Narcan?

Hydrofluoric Acid

Rust remover Glass etching Pain out of proportion Delayed onset Dysrhythmias Hypocalcemia, Hyperkalemia, Hypomagnesemia QTc prolongation and VT Topical and SQ injection of calcium gluconate for small BSA IV calcium for large BSA or ingestion

Lead

Acute: Abd pain, hemolysis, encephalopathy, seizures, death Chronic: Malaise, weight loss, arthralgias, anemia, **basophilic stippling of RBC's TX = supportive Chelators: BAL, ETDA, DMSA

Lithium

Tox usually from drug-drug NSAIDs, ACEi's, Diuretics N/V/D, tremors, cardiac Cardiac usually not clinically significant Charcoal doesn't work (metals) WBI Renal elimination only (HD) IVF

Dilantin

Gingival hyperplasia Oral toxicity = CNS depressant, cerebellar dysfunction, seizures uncommon, NO CARDIAC IV toxicity = Hypotension (not seen with phosphenytoin)

Carbamazepine

Sodium channel blockade and QRS widening Treat with bicarb Seizures at high doses SIADH and hyponatremia at high doses

Serotonin Syndrome

``` AMS Febrile Mydriasis Agitation Rigidity/Tremor LE>UE **Clonus ``` Must have exposure to serotonin ``` MAOI Lithium SSRI DXM TCA's Demerol Ecstasy ```

Hypoglycemic agents

``` Ethanol (peds) Insulin B-blockers (peds) Salicylates Quinine ``` Not metformin (lactic acidosis)

Anion Gap Metabolic Acidosis

``` Methanol Uremia DKA Paraldehyde INH/Iron Lactic Acidosis Ethylene Glycol Salicylates ```

Toxicology Flashcards

(48 cards)